Metal bending machine



Oct. 5, 1965 J. E. TEPLOW METAL BENDING MACHINE 2 Sheets-Sheet 1 Filed Feb. 12, 1962 F IG.

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JOSEF E. TEPLOW 7 7m1-mk) ATTORNEYS Oct. 5, 1965 J. E. TEPLOW 3,209,577

METAL BENDING MACHINE Filed Feb. 12, 1962 2 Sheets-Sheet 2 INVENTOR. F I 3 JQSEF E. TEPLOW ATTORNEYS United States Patent 3,209,577 METAL BENDIN G MACHINE Josef E. Teplow, 56 Boylston St., Brockton, Mass. Filed Feb. 12, 1962, Ser. No. 172,577 Claims. (CL 72-389) This invention relates in general to metal bending machines and more particularly is directed towards a new and improved strip metal bending apparatus that may be operated manually or by power.

In fabricating certain metal products such as cutting dies and the like in which a length of relatively thick metal stock is given a series of angular bends, strip metal typically is bent by heating a selected area of the stock and applying a bending force to the area. Conventionally, a fixed post and a lever operated sliding block provide the bending force for the heated metal stock. In the past the moveable block has been operated by hand a good deal of strength is required to drive it even though the metal is heated to incandescence. Although a number of power operated machines have been developed, none have possessed the proper responsiveness or sensitivity required for full and accurate control over the bending of .the metal and in many applications, such as the forming of a cutting die which may have very irregular contours, constant and precise control must be maintained over the moving block to insure that the finished product has the exact configuration specified.

In forming such products by conventional devices, a good deal of time is lost in heating and reheating the joints which are being bent. This practice is quite time consuming and adds considerably to the cost of the product. Also, the expense involved in supplying a large quantity of heating gases such as acetylene is a factor which is reflected in the final cost of the product. Furthermore, the task of bending the metal stock by means of conventional mechanism is extremely arduous even though the stock is heated, and metal benders heretofore have had to possess both skill and strength to practice their art. Due to the fatiguing nature of their work, it is difficult for metal benders to maintain a high level of efficiency over extended periods and back ailments are common among their class in later life.

Accordingly, it is an object of the present invention to provide a metal bending apparatus that may be operated either by power or manually, conveniently and with a high degree of precision.

Another object of this invention is to provide a power operated bending apparatus which may be precisely controlled by the operator.

Still another object of this invention is to provide a metal bending apparatus in which metal stock may be readily bent at room temperature and in which operation of the apparatus may be switched back and forth between power and manual control instantaneously and selectively by the operator.

More particularly, this invention features a metal bending apparatus in which a movable metal bending element is drivingly engagcable by both a power actuator and a manually operated lever, either of which may be selectively brought to bear against the movable element.

As another feature of this invention, both the power and manual components are arranged for separate or simultaneous operation without the interference of one with the other.

But these and other features of the invention, along with further objects and advantages thereof, will become more readily apparent from the following detailed description with reference being made to the accompanying drawings in which;

FIG. 1 is a top plan view of a metal bending apparatus made according to the invention,

3,209,577 Patented Oct. 5, 1965 FIG. 2 is a view in side elevation of the apparatus shown in FIG. 1,

FIG. 3 is a cross sectional view taken along the line 3-3 of FIG. 1 on an enlarged scale, and

FIG. 4 is a schematic view of the hydraulic system used to operate the power mechanism.

Referring now to the drawings, reference character 10 generally indicates a ruged, fiat rectangular bed supported by legs 11 and having an upright post 12 mounted cen- {trally thereon. One side of the post has a tapered configuration which mates with a recess 14 formed in a movable block 16. The block 16 is aligned with the post 12 and is fastened securely to a rectangular slide 18 which is mounted for free linear movement within a recess 20 formed in the upper surface and at one side of 'the bed 10. The recess 20 is somewhat longer than the 'slide 18 which is arranged to reciprocate within the recess to and away from the fixed post 12.

Pivoted to an extension of the bed 10 for rotation about a vertical axis by means of a pin 22 is an elongated lever arm 24 which has a cam 26 integral with its inner end. The cam is arranged to bear against the outer end of the slide 18 so that a clockwise rotation of the lever arm will drive the slide and the block forcibly against the post 12. It will be readily understood that by reason of the mechanical advantage of the lever and cam arrangement, metal strip stock fed into the bite of the block and post may be bent by supplying sufi'icient physical force against the lever. In practice, when stock is to be bent by operation of the lever, selected areas of the metal are heated to incandescence by :an acetylene gas torch to make the metal more workable.

Mounted on the underside of the bed 10 is a hydraulic unit 30 which includes a cylinder 32 and a piston 34. The piston is provided with a rod 33 having an enlarged head 35 which engages the lower end of a rocker arm 36. The rocker arm 36 is mounted for angular movement about a horizontal axis by means of a shear pin 38, the ends of which are supported by a pair of spaced brackets 40 depending from the underside of the bed 10. The upper end of the rocker arm extends up through an opening 42 formed in the bed 10 and an opening 44 formed in the slide 18 to bear against an inner wall 45 of the opening 44 so that the slide 18 and the block 16 will be urged towards the post 12 upon actuation of the hydraulic unit 30.

It will be noted in FIG. 3, the working end surfaces of the rocker arm 36 are profiled in such a manner that the lines of contact on both the slide 18 and the piston rod head 35 remain substantially constant over the entire range of operation of the rocker arm. As shown, the upper end of the rocker arm contacts the slide 18 approximately in the center of the wall 45 and, as the rocker arm is pivoted about its pin 38, the profiled working face of the rocker arm will move down over substantially the same area of contact. The lower end of the rocker arm functions in a similar manner with the head 35 so that the vector forces acting against the rocker arm and the slide are not altered during a power stroke of the piston 34. In practice the rocker arm is fabricated from a metal having a hardness rating of about 45 on the Rockwell C scale in order to withstand the high working pressures.

It will be appreciated that the apparatus may be operated either manually or by power or both simultaneously at the discretion of the operator. In order to provide the operator with full and complete control over the apparatus, a microswitch 46 is conveniently mounted on the lever 24 in a position where it may be readily depressed as needed. The microswitch, through suitable circuitry, actuates the hydraulic unit 30 so that the operator may instantaneously shift back and forth between manual and power control. This freedom of control makes possible very accurate bending of the stock so that the resulting product may be maintained within very close tolerances. Since the power unit 30 can apply a considerable force against the slide 18, metal stock usually may be bent in a cold condition with heating being required only where the operator wishes to bend relatively thick stock by use of the lever only, or make sharp bends by the use of power. When using power less heating of the stock is required than when bending by hand and the bend can be made quicker and with fewer steps. The resulting bend that has been made by operation of the power unit is generally of finer quality than a similar bend made with conventional equipment and considerably less effort is ex pended.

Referring now more particularly to FIG. 4, the hydraulic systems for operating the hydraulic unit 30 will be described. The system includes a pump 48 driven by a motor 50 and taking suction on a sump tank 52. The pump delivers a steady flow of hydraulic fluid along a conduit 54, through a variable pressure relief valve 56, a flow control valve 58 to a solenoid actuated valve 60. The solenoid actuated valve is connected to the microswitch 46 by means of leads 62, 64 and, depending upon whether the microswitch is open or closed, hydraulic fluid will be directed from the solenoid actuated valve 60 either to the hydraulic unit 30 or to the sump 52 through a return conduit 66. A line 68 branches into the return conduit 66 from the relief valve 56.

While the invention has been described with particular reference to the illustrated embodiment it will be understood that numerous modifications thereto will appear to those skilled in the art. It will also be understood that the foregoing description has been made in an illustrative sense and should not be taken as limiting the scope of invention which is defined in the appended claims.

Having thus described my invention, what I claim and desire to obtain by Letters Patent of the United States is:

1. A combination manual and power operable bending machine, comprising a support, a fixed member mounted on said support, a moveable member mounted on said support and adapted to reciprocate to and away from said fixed member, a cam pivotally mounted on said support and engageable with said moveable member, levers means operatively connected with said cam for manually pivoting said cam and advancing said moveable member toward said fixed member, fluid motor means drivingly engageable with said moveable member for advancing said moveable member toward said fixed member independently of said cam, a motor-driven pump for supplying fluid to said fluid motor, conduit means interconnecting said pump and said fluid motor, valve means in said conduit normally blocking fluid flow from said pump, and actuating means mounted on said lever means for selectively opening said valve means to fluid flow from said pump thereby actuating said fluid motor.

2. A combination manual and power operable bending machine, comprising a horizontal platform, an upright post mounted on said platform, said post having a tapered side edge portion, a movable block slidably mounted on said platform and adapted to reciprocate to and away from said post, said block having a recess adapted to mate with said edge, a cam pivotally mounted on said platform and drivingly engageable with said block, lever means operatively connected with said cam for manually pivoting said cam and advancing said block toward said post, a rocker arm pivotally mounted to said platform, one extremity of said arm being engageable with said block and power reciprocating means engageable with the other extremity of said arm, said power reciprocating means being adapted to pivot said arm and drive said block toward said post independently of said cam, said lever arm being adapted to pivot said cam and drive said block independently of said power means.

3. A combination manual and power operable bending machine according to claim 2 including switching means mounted on said lever means for selectively actuating said power reciprocating means.

4. A combination manual and power driven bending machine, comprising a platform, a fixed abutment mounted on said platform, a movable jaw member slidably mounted on said platform and adapted to reciprocate to and away from said abutment, a cam pivotally mounted on said platform and engageable with said movable jaw member, lever means operatively connected with said cam for manually pivoting said cam and advancing said movable jaw member forcibly towards said abutment, power reciprocating means mounted adjacent said movable member, said power means being adapted to reciprocate along a path parallel to the path of travel of said movable jaw member, a rocker member pivotally mounted to said platform between said movable member and said power reciprocating means, said rocker member having a pair of radial arms extending into contact with said movable member and said power reciprocating means whereby said rocker member may be pivoted and said movable member advanced towards said abutment upon actuation of said power reciprocating means.

5. A combination manual and power driven bending machine according to claim 4 wherein the end portions of said arms are profiled so that the lines of contact on said movable member and on said power reciprocating means remains substantially constant during pivoting of said rocker member.

References Cited in the file of this patent UNITED STATES PATENTS 810,818 1/06 Stevenson 153-21 1,719,875 7/29 Cooper 29-252 1,754,046 4/30 Rafferty 74625 1,883,335 10/32 Braden 76107 2,319,9-15 5/43 Bolsten 15348 2,668,571 2/54 Leskiewicz et al 15348 2,769,228 11/56 Burge et al 153-21 XR 2,981,131 4/61 Mitchell 269-221 XR CHARLES W. LANHAM, Primary Examiner.

WILLIAM J. STEPHENSON, Examiner. 

1. A COMBINATION MANUAL AND POWER OPERABLE BENDING MACHINE, COMPRISING A SUPPORT, A FIXED MEMBER MOUNTED ON SAID SUPPORT, A MOVEABLE MEMBER MOUNTED ON SAID SUPPORT AND ADAPTED TO RECIPROCATE TO AND AWAY FROM SAID FIXED MEMBER, A CAM PIVOTALLY MOUNTED ON SAID SUPPORT AND ENGAGEABLE WITH SAID MOVEABLE MEMBER, LEVERS MEANS OPERATIVELY CONNECTED WITH SAID CAM FOR MANUALLY PIVOTING SAID CAM AND ADVANCING SAID MOVEABLE MEMBER TOWARD SAID FIXED MEMBER, FLUID MOTOR MEANS DRIVINGLY ENGAGEABLE WITH SAID MOVEABLE MEMBER FOR ADVANCING SAID MOVEABLE MEMBER TOWARD SAID FIXED MEMBER INDEPENDENTLY OF SAID CAM, A MOTOR-DRIVEN PUMP FOR SUPPLYING FLUID TO SAID FLUID MOTOR, CONDUIT MEANS INTERCONNECTING SAID PUMP AND SAID FLUID MOTOR, VALVE MEANS IN SAID CONDUIT NORMALLY BLOCKING FLUID FLOW FROM SAID PUMP, AND ACTUATING MEANS MOUNTED ON SAID LEVER MEANS FOR SELECTIVELY OPENING SAID VALVE MEANS TO FLUID FLOW FROM SAID PUMP THEREBY ACTUATING SAID FLUID MOTOR. 